Drilling & Grouting is one of primary activities within KARST Ltd. scope of works as GT contractor expert. In diverse forms and types, D&G, as geotechnical technique may be applied at different natural and/or artificial environments/objects/structures, at different phases of works. Grouting can take place in soil and rock formations, but also within structures; before, during and/or after main construction.
With respect to grouting materials – dry component; a basic materials are: cement, bentonite and sand. Subject to physical and chemical properties of soil/rock to be grouted, and specific conditions at the site; various friendly environmental additives, mainly polimers, may be used.
Grouting categories are quite a few and are subject to final task, i.e.: main purpose of specific activity.
The primary ones are:
- grout curtain: preventing erosion and water loss at accumulations by developing and/or improving the watertightness/permeability of foundation soil/rock masses; thus avoiding understreaming of ground water beneath dams and similar structures. Works consist of plugging a grout mixture under the pressure into/inside the caverns/pores/fractures and/or any other kind of openings;
- consolidation grouting: strengthening bearing capacity of the foundation ground;
- contact and prestress grouting: stabilization/improving contacts between different materials/media (concrete-rock-steel) within structures; such as: prestressing of tunnels’ coating;
- remedial grouting: rehabilitation of exhausted/damaged walls – structures in general
Besides above stated, there are several other practices of grouting, applying in construction works; i.e.: geotechnical works:
- forming of split-up/separation walls/basins, in order to prevent mixing of potable aquifers with waste or salt/maritime waters.
- execution of piles with different diameters in soft/non coherent soils; known as “jet grouting”
- grouting during installation of temporary/permanent anchors
However; the most significant activities among grouting works (all of a/m) are these ones related to construction/rehabilitation of dams and affiliated hydro- technical structures such as:
- coffer dams; .
- diversion tunnels/channels;
- outlet tunnels/channels;
- adjacent underground structures: water intakes/outlets; water pressure shafts; penstocks; machine halls; generator halls; transformer halls and likewise.